1. Field of the Invention
The present invention relates generally to a downhole tool for use in oil field applications. In particular, this invention relates to an anchor for use with a work string, such as coiled tubing, in a wellbore, such as a horizontal wellbore.
2. Brief Description of Related Art
In recent years there has been a large increase in the number of wells that have been drilled with horizontal portions. When servicing or completing these kinds of wells it is common to use coiled tubing to convey the tools or instruments to the portion of the wellbore of interest, owing to its flexibility and speed of deployment compared to other methods. Compared to traditional drill pipe, coiled tubing is quite thin walled, and subject to buckling if a large compressive force is applied to it.
If the bottom sealing elements on a selective frac packer fail, a net upward force is generated due to the pressure contained between the upper sealing device(s) and the toe of the well. This upward force can result in the coiled tubing buckling under the compressive loading. The upward force can be mitigated in wells comprised of 4.5 inch casing or smaller, however in wells with 5.5 inch casing or larger the hydraulic forces can easily exceed 200,000 psi. In order to prevent buckling of the coiled tubing, it is necessary to provide a device that can transmit the upward compressive force in the event of a seal failure away from the coiled tubing and to the casing and thereby to the earth, rather than allowing the coiled tubing to be subjected to the compressive force.